Project Apollo: The Beginnings
| Mission Planning
| Landing Site Selection
| Earthbound Support Systems
Astronaut Selection and Training | The Saturn V | The Saturn 1B | The Apollo Spacecraft
Guidance and Navigation | Command and Service Modules | The Lunar Module
Assembling and Launching | Pathfinders | The Early Missions | Apollo 11, The First Landing
The Intermediate Missions | Apollo 15 Exploration | Apollo 16 Exploration | Apollo 17 Exploration
Skylab and Apollo-Soyuz | Conclusion
The target for the last moon landing by Apollo 17 was the Taurus-Littrow highland and valley area on the south-eastern rim of the Mare Serenitatis (Sea of Serenity). The crew were Mission Commander Eugene A Cernan, Lunar Module Pilot Harrison H 'Jack' Schmitt and Command Module Pilot Ronald B Evans. Jack Schmitt was the only professional scientist/geologist in NASA's team of astronauts and was to be sent to the moon for the last mission, as NASA did not want to miss the opportunity to send a scientist. His presence in the field was expected to give an invaluable interpretation where only a geologist could make an informed, on the spot analysis. Schmitt had originally been part of Dick Gordon's crew due to fly in Apollo 18; but on cancellation of the last two lunar missions, Schmitt was brought forward to Apollo 17 and replaced LM Pilot Joe Engle.
The landing site for Apollo 17 was in a seven mile wide valley in the Taurus mountain range which formed the outer, south-eastern rim of the Mare Serenitatis, into which the Littrow Crater had been punched 17 miles north of the selected landing spot. The valley site was surrounded on the northern, southern and eastern sides by massif's, single monolithic blocks which formed the Taurus range, and held a number of attractions for the geological team. The massifs were thrown up by the impact of an asteroid that had created the Serenitatis Basin, one of the earliest collisions in the moon's evolution which pre-dated even the Imbrium event.
The valley floor was unusually dark for a highland site which suggested relatively recent volcanic activity. It was thought to be due to a coating of volcanic ash laid down within the last half billion years which had not yet faded from the gardening effect of micro-meteorite rain. Also running from the lower slopes of the South Massif was a fan of highly contrasting white mantle that radiated across part of the valley floor and appeared to have originated from a landslide on the South Massif's face.
Running along the lower flank of the North Massif, across the valley floor and through the South Massif's white mantle was a scarp ridge rising more than 200 feet which appeared from the photographic reconnaissance pictures to be barring the way to the South Massif. A feature commonly seen on mare sites, but not previously visited by Apollo crews, it was thought to have been created by the contraction of the cooling lava flow that had filled the valley. At the eastern end of the valley, the floor rose up to form a series of regular dome shaped hills, which were given the name of the 'Sculptured Hills'.
Al Worden, overflying in Apollo 15, had photographed the Taurus-Littrow site as one of a number of possible landing sites and spotted boulders at the base of the massifs with tracks that could be traced back to their points of origin on the high slopes of the massifs. Sampling these rocks would allow access to the massif's higher levels, with the possibility of retrieving some of the oldest rocks yet found. Worden had also spotted groups of craters with dark surrounding halo's that suggested that they were volcanic in origin and could provide evidence that the moon's inner core may still be active. Some of the dark haloed craters lay in a cluster in the central floor of the valley. All in all Taurus-Littrow promised to be a geologist's paradise.
Apollo 17 was the only night launch of the Apollo series. To obtain favourable lighting conditions for the landing at the Taurus-Littrow site, which was over 20 degrees north of the lunar equator and 30 degrees east of its visible centre, would require a Trans Lunar Injection burn over the Atlantic Ocean instead of the Pacific. That in turn required a night take off to begin the TLI burn from a suitable position. The flight planners' confidence in their abilities was by now sufficient to allow them to waive their own safety rules that permitted launches to be undertaken only in daylight hours. The Atlantic TLI burn also had the advantage of a more fuel efficient trajectory and therefore a heavier payload could be carried.
At T minus 30 seconds in the launch countdown, the automatic launch sequencer, which conducted the myriad of functions during the countdown, failed to pressurize the third stage propellant tank, recognized the fault, and stopped the countdown. The launch was delayed for 2 hours 40 minutes while launch control worked its way around the fault. At last, at 12.33am on the 7 December, 1972, the last Apollo moon mission launched from pad 39a. The entire surrounding countryside around the Cape Kennedy launch site was lit up as if by daylight, as Apollo 17 ascended into the heavens. The time lost to the launch delay was made up with a longer than planned TLI burn to speed up the outbound flight.
On 11 December, Cernan and Schmitt separated their lunar module Challenger from Ron Evans in the command module America and descended to a textbook landing within 650 feet of their designated point in Taurus-Littrow at 20.16 degrees north and 30.77 degrees east.
Cernan: Okay, Houston, the Challenger has landed.
Then to Schmitt: Boy, when you said shut down, I shut down and we dropped didn't we?
Schmitt: Yes sir, but we is here.
Cernan (referring to Evans in the CM): Houston, you can tell America that Challenger is at Taurus-Littrow.
The First EVA, ALSEP and Steno Crater
As I step onto the surface at Taurus-Littrow I'd like to dedicate the first step of Apollo 17 to all those who made it possible.
- Eugene A Cernan, mission commander
The crew unloaded the Lunar Rover without problems, the deployment hinge, which had failed on the previous two missions, managed to hang together during this landing. Cernan took the Rover for a short test drive and parked alongside the MESA to load up and set up the television camera. As he aligned the aerial he called to Schmitt, 'Oh man... Hey, Jack, just stop... you owe yourself 30 seconds to look at the Earth.' Schmitt replied, 'Ah... you see one Earth, you've seen 'em all.'
Cernan planted the Stars and Stripes. The flag brought on Apollo 17 had hung in the mission control office throughout all the previous missions. Schmitt took the usual tourist photos of Cernan saluting the flag, including one inspired shot from a low angle showing Cernan, the flag and the earth above.
They turned next to laying out the ALSEP package west of the landing site near a twelve foot high boulder protruding from the surface. The package included another try at installing the Heat Flow Experiment (HFE) and a Lunar Seismic Profiler Experiment (LSPE), which involved laying out a Y-shaped series of four geophones and laying explosive charges throughout the three planned Rover excursions. The rock was immediately dubbed 'Geophone Rock'.
This time the heat flow experiment was installed without difficulty and Mark Langseth, the experiment's chief scientist probably breathed a sigh of relief as the experiment began returning data. The accompanying deep core sample again proved troublesome to remove, as it jammed fast in the regolith. Cernan's exertions to remove the core was causing him to use his oxygen and cooling water at a higher than acceptable rate, as he tried to withdraw the sample from the clinging soil. Schmitt was called to his assistance by mission control and they both applied their weight to a treadle jack that had been fitted to the core tube to get it to move. In doing so Schmitt jumped on the lever, slipped and took a spectacular fall, sending tools and dust flying as his foot kicked out and caught the tool carrier. Eventually their efforts paid off and the core began to pull out.
Cernan's difficulties with the core sample had not only put him 30 minutes behind schedule but eaten into his oxygen reserve. Mission control decided to curtail the first Rover excursion which was to follow the ALSEP deployment. Instead of a planned two mile trip to Emory Crater in the valley's central cluster, the journey was shortened to a similar crater named Steno at the closest edge of the cluster, one mile out from the landing site.
While loading the Rover Cernan's rock hammer, which was lodged in his suit's thigh pocket, caught the Rover's rear wheel dust guard, pulling it adrift in a replay of the similar Apollo 16 incident. Cernan had to fashion a repair with duct tape before setting off to safeguard the equipment on the Rover from a rooster tail of dust that would be thrown up by the unguarded wheel. Meanwhile, Schmitt could be heard keeping up a steady stream of corny songs and ditty's:
I was strolling on the moon one day...
Cernan and Schmitt together: In the merry month of ...
Cernan: No, May, May is the month...
Schmitt: May... That's right May... when much to my surprise, a pair of bonny eyes... la de dada ...
Mission scientist Bob Parker (acting as Capcom broke in): Sorry about that guys, but today 'may' be December...
Driving South towards Steno and its large boulder field they realised that, due to uncertainty of their precise landing point, they were unable to identify their correct position. They chose another smaller 60 feet diameter crater near Steno's estimated position, which had large blocks around its rim, indicating that it had excavated underlying bedrock and sampled that as an alternative.
They also laid out the first of eight explosive charges that were to be placed throughout the three EVA's and set off by a remote signal from the CM after their departure from the surface. The shock waves from the charges would be read by the Seismic Profiler through the geophones and used to investigate the depth and composition of the valley floor.
Another experiment carried on the Rover was a portable Lunar Traverse Gravimeter Experiment.(LTGE). It was to measure the gravity field at various points around the valley, which would give an insight into the varying densities of the materials that made up the valley floor and the surrounding hills. Cernan took the first of the readings at Steno and would repeat the procedure at each of the sampling stops on the three EVA's.
Mission control were becoming concerned that the crew's expendable reserves of oxygen and water were becoming depleted and Parker gave them another reminder: 'We'd like to have you guys driving in ten minutes'. 'Nag nag nag', replied Schmitt.
During their race back to the LM the damaged dust guard became detached and lost. They arrived at the LM covered in dust after seven and a half hours on the surface.
The Second EVA, The South Massif
The crew were woken from their rest period by mission control playing Wagner's 'Ride of the Valkeries' at full volume. They passed on details of a repair that they had devised overnight to replace the Rover's missing dust guard. Cernan was to fashion a replacement guard from plastic sheathed maps and duct tape and fix it to the Rover before moving out on the second traverse.
The trip to the South Massif, five miles distant was to be the longest journey away from the safety of the LM undertaken by any Apollo crew. The traverse would pass through the scarp via a fault that provided a step in its inclined face, which was appropriately named 'Hole in the Wall'. Having negotiated the scarp they would continue across the white mantle at the base of the Massif and to one of the haloed craters named 'Shorty'. On their return they were to sample another 1,800 feet wide crater, 'Camelot'.
Cernan's driving on the previous trip through the boulder field to Steno had been slow and mission control were worried that he might not complete the trip in the available time. But the terrain was not as rough as the previous journey and Cernan pressed the Rover flat out across the valley floor passing by Camelot Crater as they headed towards the scarp and the South Massif. Approaching the Massif across the light mantle now dubbed 'Tortilla Flats', both crewmen found the reflected light from the white floor to be almost blinding in contrast to the near black surface at the landing site.
In fact, the scarp proved to be more of a steadily inclining ridge than a barrier and the Rover negotiated the 'Hole in the Wall' cleft easily. Due to the time taken for the fender repair, mission control had decided to omit the sampling stop scheduled at the scarp and press on to Nansen Crater (named after the Norwegian explorer, Fridtjof Nansen) at the base of the 7,500 foot high Massif. They stopped at Nansen for one of the longest sampling stops of any mission taking a full 63 minutes. One of the rocks gathered there proved to be the oldest found on any Apollo mission, dating back 4.5 billion years.
Starting their return they rocketed downhill off the massif's lower slopes and turned north-east towards their next stop further along the base of the slope to Lara Crater. They began sampling at the edge of an adjacent smaller 30 foot crater below Lara's rim. Schmitt, trying to take samples single handed, kicked over the sample bag spilling his hard won samples. He kneeled to retrieve them and lost his balance as he tried to regain his feet. Flailing wildly as he struggled to get upright again, he fell forward onto his chest and his camera. Parker, watching this performance, asked Cernan to go over and help him to recover.
Schmitt dusted himself down and checked the camera, which had survived the impact, but bent the mounting bracket to his suit. Meanwhile Cernan was having difficulties with the click locks on his sampling tool extension handle and the Rovers catch on its tailgate, all of which were becoming clogged with dust and unworkable. Clearing them was eating into the stops time and what was supposed to have been a brief stop had now used more than its allotted half hour. Cernan asked what was next on the agenda. Parker, realising that the EVA was still running late, replied, 'Nothing, get on the Rover and leave!' Parker then advised Schmitt that the Houston Ballet Company were requesting his services after watching his earlier fall. In response, Schmitt tried a downhill ballet leap with extended leg and promptly fell again. 'How's that?' he asked. The crater was later named 'Ballet'.
The excursion continued along the edge of the landslide, picking up grab samples from the Rover with the use of a long handled scoop to save time disembarking from the Rover. One of the samples collected here was later to help identify the age of Tycho Crater at 101 million years, from which it was thought to have been ejected.
Leaving the slopes of the South Massif behind they drove off the White Mantle to their next stop, Shorty Crater, which stood out from its surroundings on the survey photographs with a dark halo. It was hoped that it would be a volcanic fumerole, a volcanic vent that had sprayed the surrounding ground with dark volcanic ash creating the halo. Cernan drove up to the rim to find the 300 foot crater had large blocks on the edge of the rim and a raised peak in the centre of the crater's floor. Schmitt descended down the outer flank of the crater to inspect a large boulder; and as he turned to regain the height of the rim to take photographs he noticed that his footprints had exposed a different coloured soil.
'Oh hey!' he exclaimed, 'Wait a minute... there's orange soil.'
'Well don't move until I've seen it.' replied Cernan.
The orange material implied that the soil had been oxidized by the action of volcanic gasses and would prove volcanic activity in the area. Working together Cernan and Schmitt dug a sampling trench to see the extent of the coloured material, which was found to be bounded by dark grey deposits on either side. Meanwhile the announcement of the find was creating great excitement in the geology team's back room. They asked Schmitt to take a double length core sample. 'Do you want it in the orange?', asked Schmitt, meaning did they want the core angled to go through the dark halo material and into the various shades of crimson, orange, and yellow soil that he had exposed in the sides of his trench, which contrasted strongly with the surface grey. 'Roger, that's affirm... We can put cores in grey soil anytime.' Parker retorted.
In fact, Shorty was not a fumerole, as had been hoped, but an impact crater. Both the orange and dark material were pyroclastics originating from much earlier volcanic action contemporary with the lava flow that had formed the valley floor. A thin layer of lava had subsequently covered the coloured material, before the gardening effect of the micro meteorite rain could churn the exposed material into the regolith. Much later, the impact that formed Shorty Crater had overturned the valley floor deposit exposing the dark and orange coloured soil.
Leaving Shorty they ran the Rover back across Tortilla Flats to their next port of call, Camelot Crater. At 1,800 feet diameter Camelot was the largest crater in the dark central plain with a spread of rocks ejected onto its southern rim. Still running hard up against the time limits imposed by the walk back constraint they hurried to collect samples and soil samples. After a short stop Parker announced, 'We'd like you to leave immediately, if not sooner'. Both astronauts broke into a gallop back to the Rover, Cernan singing an improvised version of the song 'Mule train'. Their return to the LM concluded the penultimate moon walk, which had again set new records for time on the surface and distance travelled at 7.6 hours and 14.5 miles, records which could not be broken by the final EVA's planned route.
The Third EVA, North Massif and the Sculptured Hills.
The last Apollo moon walk was to be a circular route to the north-east corner of the valley, three miles from the landing site to the base of the North Massif and then to the Sculptured Hills north-west of the massif. The return would take in two large craters Van Serg and Sherlock.
The outbound trip took them to Turning Point Rock, a house sized boulder sitting in the middle of the valley floor which appeared in the reconnaissance photographs to have rolled down from the North Massif. Although not a scheduled stop, Cernan drove the Rover around the rock to allow Schmitt to appraise it and take a couple of quick grab samples from the Rover using the long handled scoop. Turning east, they were soon in a boulder field on the 20 degree slope at the base of the North Massif, their objective another giant rock with its trail down the mountainside where its origins could be traced to the upper levels. The rock was the largest yet visited, but could be seen to have split into several pieces where it had come to rest. Schmitt went to sample it while Cernan attended to the gravimeter.
While sampling around the rock, it became clear to Schmitt that it had undergone a number of transformations in its evolution. It consisted of both blue-grey and tan-grey materials that corresponded to those in the levels of the massif above. The rock showed the events which had created the surrounding massifs.
The blue-grey was a breccia and the tan-grey an impact melt breccia from the original Serenitatis collision, when an asteroid travelling at speeds of up to 10 miles per second had impacted into the moon's crust with the force of many H-bombs. The shock wave, spreading outwards like ripples on a pond from a thrown stone, had pushed the partly solidified crust outwards and upwards, forming the circular mountain ranges. The pulverized and melted material from the centre of the impact which excavated the basin was thrown upwards into a ballistic trajectory to return and overlay the newly formed mountain ranges.
The upper surfaces of the rock were layered with thick dust; and Cernan realised, as he drove the Rover off to their next site, that he had missed the opportunity to write his daughter's name, Tracy, in the dust. Nevertheless, when he later told of his regret at the mission de-briefing, the rock was named 'Tracy's Rock'.
They drove off the North Massif and, cutting across the corner of the plain to the slopes of the Sculptured Hills, made two sampling stops on the way. There were few large rocks accessible to them at the foot of the hills and Schmitt climbed 50 yards up the slope to get to the only available one in the vicinity, which he tried to dislodge with his boot and roll down to Cernan. It wouldn't roll and Schmitt yelled at the rock, 'Go! Roll! ...I'd roll on this slope, why don't you?' Cernan had to climb up to join him and, chipping a piece off, they found that the shocked and melted rock was coated and stained with glass. Later analysis showed the rock to have been 4.34 billion years old, pre-dating the Serenatatis event and out of character with its surroundings.
Coming down the hill back to the Rover Schmitt was taking large kangaroo hops and swinging from side to side impersonating a skier as he made schussing noises: ' ...I can't keep my edges'. Regaining the Rover and leaving the Sculptured Hills they headed at full speed back across the plain towards Van Serg, a dark floored, 250 foot crater in the middle of a cluster. Passing into the cluster they found the ground so heavily strewn with rocks that they were only able to get the Rover to 75 yards from its southern rim. Schmitt approached the craters rim on foot singing 'Tiptoe through the tulips'.
It was soon obvious that Van Serg's dark floor was not due to volcanism. It had been created by a primary impact dating within the last four million years, which had struck a particularly thick part of the regolith built up from the ejecta of the surrounding craters. The impact had not penetrated to the underlying lava floor of the valley to bring up the lighter-coloured sub floor rocks, leaving only the dark regolith material in the crater floor.
>From Van Serg it was a straight run home, as Schmitt was using oxygen at a high rate; and it was decided to make the last scheduled stop at Sherlock Crater a drive-by instead. Stopping nearby to check the Rover's navigation system Schmitt took the opportunity to hop off the Rover and grab the largest rock returned by Apollo 17. As he returned to the Rover he found that the latch on the tailgate, which had previously been clogged with dust and difficult to engage, had come adrift and they had lost their sampling rake and scoop. Luckily the sample container boxes were still aboard.
Returning to the LM the crew set about closing out the EVA and stowing the samples on board Challenger, during which Cernan held up a piece of rock to the TV camera. NASA was hosting students from seventy countries during the Apollo 17 mission and the rock he held, which was to become known as the 'Goodwill Rock', was to be divided among them to be taken back to their respective national museums. Cernan explained:
It's a rock composed of many fragments, of many sizes, and many shapes, probably from all parts of the moon, perhaps billions of years old. But fragments of all sizes and shapes and even colours, that have grown together to become a cohesive rock, outlasting the nature of space, sort of living together in a very coherent, very peaceful manner. When we return this rock to Houston we'd like to share this rock with so many other countries throughout the world, We hope this will be a symbol of what our feelings are, what the feelings of the Apollo program are, and a symbol of mankind, that we can live in peace and harmony in the future.
He brought the camera around to face Challenger and unveiled a plaque on the landing leg that commemorated the last Apollo landing. It read:
Here man completed his first exploration of the moon, December, 1972 AD. May the spirit of peace in which we came be reflected in the lives of all mankind.
This is our commemoration that will be here until someone like us, until some of you who are out there, who are the promise of the future, come back to read it again and to further the exploration and meaning of Apollo.
Cernan took one last reading from the portable gravimeter and asked mission control if they had finished with it. On getting their confirmation he picked up the instrument and threw it towards the horizon with an underarm throw. It described a graceful arc and landed out beyond the Rover.
Cernan drove the Rover out to a position behind the LM and parked in a position that would provide television coverage of the following days take off, while Schmitt walked out to the ALSEP site on the other side and carried out a final cleaning of the instruments to remove as much dust from them as possible and to try, unsuccessfully, to get one of the experiments, the Lunar Surface Gravimeter (LSG), to function correctly with a few judicious taps. Cernan removed the remains of the rear wheel fenders to return with him to earth where they eventually ended up on display in Washington's Smithsonian Air and Space Museum, and the Johnson Space Centre Visitor's Centre. Both Cernan and Schmitt returned to the LM; and Schmitt climbed the ladder to the cabin. Cernan remained at the foot of the LM's ladder; and, as he stood alone, the last man on the moon, he called back to mission control:
Bob, this is Gene, and I'm on the surface... and as I take man's last step from the surface, back home for some time to come, but we believe not too long into the future, I'd like to just say what I believe history will record, that America's challenge of today has forged man's destiny of tomorrow. And as we leave the moon at Taurus-Littrow, we leave as we came, and, God willing, as we shall return, with peace and hope for all mankind... God speed the crew of Apollo 17.'
At just after 188 hours Ground Elapsed Time, Challenger lifted off from the moon's surface. Ed Fendall, operating the television camera on the Rover from back in mission control and now known to the crews as 'Captain Video', caught the moment of ignition, as the explosive bolts separated the ascent stage from the redundant lower descent stage; and its covering was blown in all directions by the engine's efflux. Fendall, while allowing for a six second delay in the return signal and operation of his camera, tracked the ascent stage skyward for almost half a minute, as it rose and disappeared from view.
After rejoining and docking with America, the crew transferred the sample boxes and jettisoned Challenger to impact on the lunar surface. It's target point was the east side of the South Massif. Ed Fendall aimed the still functioning Rover's camera at the target, but was unable to record the impact, although estimates and observations from America showed it to have impacted within a mile of the planned spot.
America remained in lunar orbit for a further 40 hours to take final photographs and observations, before firing the service module's engine for the Trans Earth Injection burn to set them on the return journey to earth. One last task remained for CM pilot Ron Evans. He had to go outside and '..take out the trash', disposing of a trash bag containing the accumulated rubbish from the CM, also to retrieve the film canisters from the SIM bay. Obviously enjoying his moment while being watched by the on board TV camera , Evans enthused, 'Hot diggety dog!... Talk about being a spaceman, this is it!'
Re-entry and splashdown in the Pacific concluded the final lunar mission on 19 December, 1972; and crew and spacecraft were picked up by the USS Ticongerona. The mission returned the greatest weight of rock samples of any of the Apollo missions, weighing in at over 243 pounds. The final splashdown from a lunar mission was cheered by a crowded and jubilant mission control, who had assembled to witness the return of the last lunar mission.